In-vehicle network system

ABSTRACT

An in-vehicle network system includes a power supply, an upper electronic control unit (ECU), an intermediate ECU configured to communicate with the upper ECU, and a plurality of lower ECUs configured to communicate with the intermediate ECU. The intermediate ECU is configured to receive power supplied from the power supply and supply the power supplied from the power supply to the lower ECUs. The lower ECUs are configured to transition, when the power is supplied from the intermediate ECU, from a power-off state to a standby state to wait for an instruction. The power supply is connected to the intermediate ECU via a power line and is not connected via the same power line to the upper ECU.

INCORPORATION BY REFERENCE

This application is a Continuation of U.S. patent application Ser. No.16/862,627 filed on Apr. 30, 2020, which claims the benefit of JapanesePatent Application No. 2019-127626 filed on Jul. 9, 2019, all of whichare hereby incorporated by reference in their entirety.

BACKGROUND 1. Technical Field

The disclosure relates to an in-vehicle network system.

2. Description of Related Art

A vehicle is equipped with a plurality of in-vehicle devices each calledan electronic control unit (ECU). One mode of operation control of theECUs will be described with reference to FIGS. 3A and 3B. In the exampleshown in FIG. 3A, power from a power supply 900 is supplied to an ECU902 as battery (+B) power of a +B power supply, accessory (ACC) power ofan ACC power supply, and ignition (IG) power of an IG power supply viathree power lines 905, 906, and 907, respectively. The power line 905directly connects the power supply 900 and the ECU 902, and power isconstantly supplied by the power line 905. The power line 906 connectsthe power supply 900 and the ECU 902 via an ACC relay 903. The powerline 907 connects the power supply 900 and the ECU 902 via an IG relay904. A power supply management ECU 901 detects a user's operation ofturning on an ACC or an IG using a key or a push switch, and operatesthe ACC relay 903 via a control line 908 and the IG relay 904 via acontrol line 909 in accordance with the detected operation. For example,when detecting the ACC ON operation, the power supply management ECU 901closes the ACC relay 903 to supply power via the power line 906.Further, when detecting the IG ON operation, the power supply managementECU 901 closes the IG relay 904 to supply power via the power line 907.

The ECU 902 performs an operation in accordance with a combination ofwhether the +B power of the +B power supply, the ACC power of the ACCpower supply, and the IG power of the IG power supply are supplied viathe three power lines 905, 906, and 907. For example, when the ACC powerof the ACC power supply is supplied, the ECU 902 executes apredetermined operation determined as the operation for an ACC ON state,and when the IG power of the IG power supply is supplied, the ECU 902executes a predetermined operation determined as the operation for an IGON state. A communication line 910 connects the power supply managementECU 901 and the ECU 902, and the power supply management ECU 901 and theECU 902 can communicate with each other. One or two of the +B powersupply, the ACC power supply, and the IG power supply may be omitteddepending on the specifications of the ECU 902.

As another mode of the operation control of the ECU, a mode has beenproposed in which a function called a network management (NM) functionis added to the ECU to reduce the number of power lines compared to themode shown in FIG. 3A. The NM function includes a function that enablescontrol on a bus basis to switch the state of each ECU connected to acommunication bus between a standby state in which operation issuppressed and a startup state in which operation can be executed(Japanese Unexamined Patent Application Publication No. 2016-134855 (JP2016-134855 A)). In the example illustrated in FIG. 3B, an ECU 912includes an NM unit 913 that has the NM function, and power from thepower supply 900 is supplied to the ECU 912 only as the +B power of the+B power supply via the power line 905. A power supply management ECU911 detects a user's operation of turning on the ACC or the IG using akey or a push switch, and instructs the ECU 912 via the communicationline 910 in accordance with the detected operation.

In the standby state, the NM unit 913 waits for the above-describedinstruction from the power supply management ECU 911, and upon receivingthe instruction, shifts the ECU 912 to the startup state. Thisinstruction is a message in a format conforming to the specification ofthe NM function, and the message can include, for example, informationsuch as ACC ON and IG ON. After transitioning to the startup state, theECU 912 further executes the predetermined operations for the ACC ONstate or the IG ON state based on the information included in theinstruction. In the startup state of the ECU 912, when the NM unit 913determines that the ECU 912 may transition to the standby state based onthe operation state of the ECU 912 and communication with the powersupply management ECU 911 or the like, the NM unit 913 can cause the ECU912 to transition to the standby state.

In the example shown in FIG. 3B, the number of power lines, relays, orthe like can be reduced, and therefore costs can be reduced, as comparedwith the example shown in FIG. 3A.

SUMMARY

Since the ECU including the NM function consumes standby power even inthe standby state in which the ECU does not need to operate, the standbypower increases in a network system that includes a large number ofECUs.

The disclosure provides an in-vehicle network system in which standbypower is suppressed.

The in-vehicle network system according to a first aspect of thedisclosure includes a power supply, an upper ECU, an intermediate ECUconfigured to communicate with the upper ECU, and a plurality of lowerECUs configured to communicate with the intermediate ECU. Theintermediate ECU is configured to receive power supplied from the powersupply, and maintain the lower ECUs in a power-off state until theintermediate ECU receives a message from the upper ECU and supply thepower supplied from the power supply to the lower ECUs in response tothe message transmitted from the upper ECU. The lower ECUs areconfigured to transition, when the power is supplied from the powersupply, from the power-off state to a standby state to wait for aninstruction.

According to the first aspect of the disclosure, the intermediate ECUmay be further configured to transmit a message to the lower ECUs in thestandby state in response to the message transmitted from the upper ECU.The lower ECUs may be configured to transition from the standby state toa startup state in response to the message transmitted from theintermediate ECU.

According to the first aspect of the disclosure, the lower ECUs may beconfigured to specify an operation in the startup state in response tothe message transmitted from the intermediate ECU.

According to the disclosure, the ECU is set to the power-off stateinstead of the standby state in which the standby power is consumed, sothat it is possible to provide an in-vehicle network system in which thestandby power is suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS

Features, advantages, and technical and industrial significance ofexemplary embodiments of the disclosure will be described below withreference to the accompanying drawings, in which like signs denote likeelements, and wherein:

FIG. 1 is a diagram showing a configuration of a network systemaccording to an embodiment of the disclosure;

FIG. 2 is a flowchart showing a startup process in the network systemaccording to the embodiment of the disclosure;

FIG. 3A is a diagram showing power supply control of an ECU according tothe related art; and

FIG. 3B is another diagram showing power supply control of an ECUaccording to the related art.

DETAILED DESCRIPTION OF EMBODIMENTS

A network system according to the disclosure employs an NM function toreduce the number of power lines or the like. In the network system, anECU that does not need to be currently started is set to a power-offstate in which no power is consumed, instead of a standby state of theNM function in which standby power is consumed, and when the need forstarting the ECU occurs, power is supplied to set a startup state afterthe standby state. Thereby, the standby power of the network system canbe suppressed.

Embodiment

Hereinafter, an embodiment of the disclosure will be described in detailwith reference to the drawings.

Configuration

FIG. 1 is a diagram showing a configuration of a network system 1according to the embodiment.

The network system 1 includes a tree-type connection topology. FIG. 1shows a configuration in which two intermediate nodes are subordinate toone upper node, and three lower nodes are subordinate to each of theintermediate nodes. In FIG. 1 , an upper ECU 11 is the upper node. Afirst intermediate ECU 21 and a second intermediate ECU 22 are theintermediate nodes. First lower ECUs 31 are the lower nodes subordinateto the first intermediate ECU 21, and second lower ECUs 32 are the lowernodes subordinate to the second intermediate ECU 22. The network system1 is mounted on a vehicle and includes the ECUs described above and apower supply 10 that supplies power to the ECUs. In the followingdescription, as the intermediate nodes, two ECUs, namely, the firstintermediate ECU 21 and the second intermediate ECU 22, are provided.However, the number of the intermediate nodes and the number of thelower nodes subordinate to each of the intermediate nodes are notspecifically limited. That is, two ECUs are provided as the intermediatenodes in this embodiment, but an ECU may be provided as the intermediatenode, and three or more ECUs may be provided as the intermediate node.Furthermore, three ECUs are provided as the lower nodes subordinate toeach of the intermediate nodes in this embodiment, but two or less ECUsmay be provided as the lower nodes, and four or more ECUs may beprovided as the lower nodes.

As an example, the upper ECU 11 is a relatively highly functional ECUthat collectively performs computations for various vehicle controlfunctions. The lower ECUs such as the first lower ECUs 31 and the secondlower ECUs 32 are, for example, ECUs provided in each component of thevehicle and having relatively specialized functions for individuallycontrolling each sensor or each actuator. The intermediate ECUs such asthe first intermediate ECU 21 and the second intermediate ECU 22 areECUs that function as gateways that relay communication between theupper ECU 11 and the lower ECUs. The first intermediate ECU 21 relayscommunication between the upper ECU 11 and the first lower ECUs 31. Thesecond intermediate ECU 22 relays communication between the upper ECU 11and the second lower ECUs 32. These ECUs are typically configured toinclude a control unit such as a processor or a microcomputer and amemory.

The upper ECU 11 and the first intermediate ECU 21 are connected by acommunication line 111. The first intermediate ECU 21 and the firstlower ECUs 31 are connected by a communication line (bus) 211. The upperECU 11 and the second intermediate ECU 22 are connected by acommunication line 112. The second intermediate ECU 22 and the secondlower ECUs 32 are connected by a communication line (bus) 212.Communication between the upper ECU 11 and the first intermediate ECU 21and communication between the upper ECU 11 and the second intermediateECU 22 are performed in accordance with, for example, the Ethernet(registered trademark) standard. However, the communication standard isnot limited thereto. Communication between the first intermediate ECU 21and the first lower ECUs 31 and communication between the secondintermediate ECU 22 and the second lower ECUs 32 are performed inaccordance with, for example, the controller area network (CAN;registered trademark) standard. However, the communication standard isnot limited thereto.

The power supply 10 is connected to the first intermediate ECU 21 andthe second intermediate ECU 22 by a power line 101. The firstintermediate ECU 21 and the first lower ECUs 31 are connected by a powerline 201. Further, the second intermediate ECU 22 and the second lowerECUs 32 are connected by a power line 202. Each of the firstintermediate ECU 21 and the second intermediate ECU 22 includes a relay28. The relay 28 of the first intermediate ECU 21 can switch between adisconnected state and a connected state of the power line 101 and thepower line 201. The relay 28 of the second intermediate ECU 22 canswitch between a disconnected state and a connected state of the powerline 101 and the power line 202. Although not shown, the power supply 10and the upper ECU 11 may be connected by the power line 101, or may beconnected by another power line provided separately from the power linesdescribed above.

Each of the first intermediate ECU 21 and the second intermediate ECU 22includes an NM unit 29. Each of the first lower ECUs 31 and the secondlower ECUs 32 includes an NM unit 39. The NM units 29 and 39 have thenetwork management (NM) function described above, and perform control toswitch the state of each ECU between the standby state in whichoperation is suppressed and the startup state in which variousoperations can be executed.

The upper ECU 11 collects, for example, information on the vehicle andsurrounding conditions of the vehicle from the first lower ECUs 31 andthe second lower ECUs 32 that control the sensors. This information mayinclude, for example, operational conditions of the actuators, etc.,driving conditions of the vehicle such as vehicle speed andacceleration, environmental conditions of the vehicle such as roads andobjects surrounding the vehicle, a seating status of an occupant, anddetails of operations performed with respect to each component of thevehicle. The upper ECU 11 performs computations based on thisinformation and generates control data. The control data is data forcontrolling various functions of the vehicle, such as an autonomousdriving function, a self-parking function, drive assistance functionsincluding collision avoidance, lane keeping, automatic follow-up of thepreceding vehicle, and cruise control, operational control of an engine,a transmission, a cooling device, and an air conditioner, charging anddischarging control of a battery, lighting of headlamps in accordancewith illuminance, permission of unlocking doors based on authenticationusing a mobile device (electronic key), and presentation of informationto a user. The upper ECU 11 transmits the control data as appropriate tothe first lower ECUs 31 and the second lower ECUs 32 that control theactuators to cause the actuators to operate in accordance with thecontrol data. In the network system 1, cost is reduced by concentratingvarious control functions of the vehicle in the upper ECU 11 andrelatively simplifying the configurations of the first lower ECUs 31 andthe second lower ECUs 32 instead.

Processes

A startup process of the network system 1 according to the embodimentwill be described below. FIG. 2 is a flowchart showing the startupprocess. As an example, a description will be given with reference toFIG. 2 of a process in which, of the lower nodes, the three first lowerECUs 31 subordinate to the first intermediate ECU 21 are started as onetarget startup group. At the start of this process, the firstintermediate ECU 21 is in the standby state as an initial state. Therelay 28 of the first intermediate ECU 21 is opened such that the powerline 101 and the power line 201 are not connected, and the first lowerECUs 31 are in a power-off state.

Step S101

When determining that it is necessary to start the first lower ECUs 31,the upper ECU 11 transmits a message to the first intermediate ECU 21via the communication line 111.

The upper ECU 11 can determine whether it is necessary to start thefirst lower ECUs 31 and what operation is to be performed by the firstlower ECUs 31 when the first lower ECUs 31 are started, based on, forexample, information received from another ECU that has already beenstarted. A specific method of such determination is determined inaccordance with operation specifications of the first lower ECUs 31,operation requirements of the entire vehicle, or the like. For example,when the upper ECU 11 receives, from the ECU that controls a pushswitch, information indicating that the user has pressed the push switchto perform an operation of instructing the power supply of the vehicleto switch from the OFF state to the IG ON state, the upper ECU 11 candetermine that it is necessary to cause the first lower ECUs 31 toperform the operation for the IG ON state. The message includes aninstruction to cause the subordinate nodes to transition to the startupstate, and information used to specify the operation of the first lowerECUs 31 such as IG ON. The operation of the first lower ECUs 31 is notdefined by only the conventional power supply state such as ACC ON andIG ON, but can be variously defined in accordance with advancedfunctions of the vehicle and the ECU.

Step S102

The first intermediate ECU 21 receives the message. The NM unit 29causes the first intermediate ECU 21 to transition from the standbystate to the startup state in accordance with the instruction in themessage to transition to the startup state.

Step S103

The first intermediate ECU 21 closes the relay 28 to connect the powerline 101 and the power line 201, and starts power supply from the powersupply 10 to the first lower ECUs 31 via the first intermediate ECU 21.

Step S104

When power is supplied to the first lower ECUs 31, the NM units 39 causethe first lower ECUs 31 to transition to the standby state as theinitial state.

Step S105

The first intermediate ECU 21 converts a format of the messagetransmitted from the upper ECU 11 as appropriate in accordance with adifference in the communication standard, and relays the message to thefirst lower ECUs 31 in the standby state. Note that the firstintermediate ECU 21 can appropriately detect that the first lower ECUs31 have transitioned to the standby state, for example, throughcommunication with the first lower ECU 31 s.

Step S106

The first lower ECUs 31 receive the message. The NM units 39 cause thefirst lower ECUs 31 to transition from the standby state to the startupstate in accordance with the instruction in the message to transition tothe startup state. The first lower ECUs 31 specify and execute theoperation based on the information included in the message andspecifying the operation such as IG ON.

Step S107

Communication for controlling various functions of the vehicle isstarted. The first intermediate ECU 21 relays communication between theupper ECU 11 and the first lower ECUs 31. The first lower ECUs 31 alsocommunicate with each other. Thus, the startup process of the firstlower ECU 31 s ends. After that, when the upper ECU 11 determines thatthe first lower ECUs 31 do not need to be operated, for example, bydetecting that the user has performed an operation such as IG OFF, theupper ECU 11 causes the first lower ECUs 31 to transition to the standbystate, causes the relay 28 of the first intermediate ECU 21 to open tostop power supply, and causes the first intermediate ECU 21 totransition to the standby state, conforming to the NM function.

In the above description, the instruction to cause the firstintermediate ECU 21 and the first lower ECUs 31 to transition to thestartup state and the information used to specify the operation of thefirst lower ECUs 31 such as IG ON are included in the same message.However, the above configuration is not limited as long as a similarstartup process can be executed. For example, these instructions andinformation may be individually included in two messages separatelytransmitted from the upper ECU 11.

Modification

In the network system 1 described above, the upper ECU 11 and the firstintermediate ECU 21 are connected by the communication line 111, and theupper ECU 11 and the second intermediate ECU 22 are connected by thecommunication line 112 that is different from the communication line111. That is, the upper node and each intermediate node are notconnected by a one-to-many bus connection, but are connected by aone-to-one connection with a dedicated line. This is because, in orderfor the upper node to communicate with many lower nodes connected byeach intermediate node without interruption, providing a dedicated linebetween the upper node and the intermediate node can facilitate a designthat guarantees a sufficient band rather than bus connection. However,as a modification, a mode in which the upper node and each intermediatenode are connected by a one-to-many bus connection may be adopted. Inthis case, a part of the process described above is changed. The changesto be made will be described below.

In the mode in which the upper ECU 11 is connected to the firstintermediate ECU 21 and the second intermediate ECU 22 by a bus, themessages transmitted from the upper ECU 11 to the first intermediate ECU21 include a message for starting the first lower ECUs 31 subordinate tothe first intermediate ECU 21 and a message for starting the secondlower ECUs 32 subordinate to the second intermediate ECU 22. In stepS102, the first intermediate ECU 21 transitions from the standby stateto the startup state in accordance with the standard of the NM function,regardless of the message received.

In step S102, the first intermediate ECU 21 that has transitioned to thestartup state determines whether it is necessary to start thesubordinate first lower ECUs 31 based on the received message. Thisdetermination can be made when the upper ECU 11 transmits the messageincluding information necessary for the determination, and the firstintermediate ECU 21 refers to this information. This information may beinformation such as the IG ON described above, or may be informationthat more specifically specifies the first lower ECUs 31.

When the first intermediate ECU 21 determines that the first lower ECUs31 need to be started, the process proceeds to step 5103. When the firstintermediate ECU 21 determines that the first lower ECUs 31 do not needto be started, the first intermediate ECU 21 waits to receive the nextmessage from the upper ECU 11. Thereafter, when the first intermediateECU 21 determines that the first lower ECUs 31 need to be started basedon the next message received, the process proceeds to step 5103, andwhen the first intermediate ECU 21 determines that the first lower ECUs31 do not need to be started based on the next message received, thefirst intermediate ECU 21 repeats the process of waiting to receive thenext message.

In the embodiment and modification, the process when the first lowerECUs 31 subordinate to the first intermediate ECU 21 are started hasbeen described as an example. A similar process may be performed whenthe second lower ECUs 32 subordinate to the second intermediate ECU 22are started.

Effect

The network system 1 according to the embodiment and the modificationemploys the NM function to reduce the number of power lines or the like,and the lower ECUs that do not need to be currently started are set tothe power-off state in which no power is consumed, instead of thestandby state of the NM function in which the standby power is consumed.When the need for starting the lower ECUs occurs, power is supplied toset the startup state after the standby state. This suppresses thestandby power even when the number of the lower ECUs is large. Also, bygrouping the lower ECUs under a plurality of the intermediate ECUs,starting can be instructed in groups, so that only the lower ECUs in thegroup that need to be started can be started, and the power-off state ofthe other lower ECUs can be maintained without being started inconjunction with the group started above. Thus, power consumption can besuppressed.

The ECUs do not need to include the NM function, and the lower ECUs maybe started when the intermediate ECU starts power supply to the lowerECUs in response to an instruction from the upper ECU. Also in thiscase, the effect of suppressing power consumption by the startup controlin groups described above can be obtained.

The disclosure is not limited to the network system, and can beimplemented as a method of controlling the network system, a controlprogram for the network system to be performed by the ECU having aprocessor and a memory and a computer-readable non-transitory storagemedium that stores the control program, and a vehicle equipped with thenetwork system, etc. In addition, the disclosure can be applied tonetwork systems other than the network system mounted on the vehicle.

The disclosure is advantageous for a network system mounted on a vehicleor the like.

What is claimed is:
 1. An in-vehicle network system comprising: a powersupply; an upper electronic control unit; an intermediate electroniccontrol unit configured to communicate with the upper electronic controlunit; and a plurality of lower electronic control units configured tocommunicate with the intermediate electronic control unit, wherein: theintermediate electronic control unit is configured to: receive powersupplied from the power supply, and supply the power supplied from thepower supply to the lower electronic control units; the lower electroniccontrol units are configured to transition, when the power is suppliedfrom the intermediate electronic control unit, from a power-off state toa standby state to wait for an instruction; and the power supply isconnected to the intermediate electronic control unit via a power lineand is not connected via the same power line to the upper electroniccontrol unit.
 2. The in-vehicle network system according to claim 1,wherein: the intermediate electronic control unit is configured totransmit an instruction to the lower electronic control units in thestandby state in response to an instruction transmitted from the upperelectronic control unit; and the lower electronic control units areconfigured to transition from the standby state to a startup state inresponse to the instruction transmitted from the intermediate electroniccontrol unit.
 3. The in-vehicle network system according to claim 1,wherein the intermediate electronic control unit is in a standby statein which the power line is open, until receiving an instruction from theupper electronic control unit.
 4. The in-vehicle network systemaccording to claim 3, wherein when intermediate electronic control unitis in the standby state, the lower electronic control units are in thepower-off state.
 5. The in-vehicle network system according to claim 1,wherein: the intermediate electronic control unit is connected to thepower supply via the power line, and is connected to the lowerelectronic control units via another power line; and the intermediateelectronic control unit is in a standby state in which both the powerline and the another power line are open, until receiving an instructionfrom the upper electronic control unit.
 6. The in-vehicle network systemaccording to claim 4, wherein when intermediate electronic control unitis in the standby state, the lower electronic control units are in thepower-off state.
 7. The in-vehicle network system according to claim 4,wherein: while the intermediate electronic control unit is in thestandby state and the lower electronic control units are in thepower-off state, the upper electronic control unit determines that it isnecessary to start at least one of the lower electronic control units,and upon determining that it is necessary to start at least one of thelower electronic control units, transmits an instruction to theintermediate electronic control unit, so that the intermediateelectronic control unit transitions from the standby state to a startupstate in which both the power line and the another power line areclosed; and the intermediate electronic control unit converts theinstruction transmitted from the upper electronic control unit into aformat compatible with the at least one of the lower electronic controlunits, and transmits the converted instruction to the at least one ofthe lower electronic control units, so that the at least one of thelower electronic control units transitions from the power-off state tothe standby state.
 8. The in-vehicle network system according to claim7, wherein the lower electronic control units are configured to specifyan operation to be performed based on the converted instructiontransmitted from the intermediate electronic control unit.
 9. Thein-vehicle network system according to claim 1, wherein: there are aplurality of the intermediate electronic control unit including a firstintermediate electronic control unit and a second intermediateelectronic control unit, the power supply is connected to the firstintermediate electronic control unit and the second intermediateelectronic control unit via the same power line, the first intermediateelectronic control unit relays communication between the upperelectronic control unit and a first group of the lower electroniccontrol units, and the second intermediate electronic control unitrelays communication between the upper electronic control unit and asecond group, separate from the first group, of the lower electroniccontrol units.
 10. A method for communication in an in-vehicle networksystem including a power supply, an upper electronic control unit, anintermediate electronic control unit configured to communicate with theupper electronic control unit, and a plurality of lower electroniccontrol units configured to communicate with the intermediate electroniccontrol unit, the method comprising: receiving, by the intermediateelectronic control unit, power supplied from the power supply;supplying, by the intermediate electronic control unit, the powersupplied from the power supply to the lower electronic control units;and when the power is supplied from the intermediate electronic controlunit, transitioning, by the lower electronic control units, from apower-off state to a standby state to wait for an instruction, whereinthe power supply is connected to the intermediate electronic controlunit via a power line and is not connected via the same power line tothe upper electronic control unit.
 11. A non-transitory computerreadable medium storing an instruction for one or more processors in anin-vehicle network system, the in-vehicle network system including apower supply, an upper electronic control unit, an intermediateelectronic control unit configured to communicate with the upperelectronic control unit, and a plurality of lower electronic controlunits configured to communicate with the intermediate electronic controlunit, the instruction, when executed, causing the one or more processorsin the in-vehicle network system to perform: receiving, by theintermediate electronic control unit, power supplied from the powersupply; supplying, by the intermediate electronic control unit, thepower supplied from the power supply to the lower electronic controlunits; and when the power is supplied from the intermediate electroniccontrol unit, transitioning, by the lower electronic control units, froma power-off state to a standby state to wait for an instruction, whereinthe power supply is connected to the intermediate electronic controlunit via a power line and is not connected via the same power line tothe upper electronic control unit.
 12. The method according to claim 10,further comprising: transmitting, by the intermediate electronic controlunit, an instruction to the lower electronic control units in thestandby state in response to an instruction transmitted from the upperelectronic control unit; and transitioning, by the lower electroniccontrol units, from the standby state to a startup state in response tothe instruction transmitted from the intermediate electronic controlunit.
 13. The method according to claim 10, wherein the intermediateelectronic control unit is in a standby state in which the power line isopen, until receiving an instruction from the upper electronic controlunit.
 14. The method according to claim 10, wherein: the intermediateelectronic control unit is connected to the power supply via the powerline, and is connected to the lower electronic control units via anotherpower line; and the intermediate electronic control unit is in a standbystate in which both the power line and the another power line are open,until receiving an instruction from the upper electronic control unit.15. The non-transitory computer readable medium according to claim 11,wherein the instruction, when executed, causes the one or moreprocessors in the in-vehicle network system to further perform:transmitting, by the intermediate electronic control unit, aninstruction to the lower electronic control units in the standby statein response to an instruction transmitted from the upper electroniccontrol unit; and transitioning, by the lower electronic control units,from the standby state to a startup state in response to the instructiontransmitted from the intermediate electronic control unit.
 16. Thenon-transitory computer readable medium according to claim 11, whereinthe intermediate electronic control unit is in a standby state in whichthe power line is open, until receiving an instruction from the upperelectronic control unit.
 17. The non-transitory computer readable mediumaccording to claim 11, wherein: the intermediate electronic control unitis connected to the power supply via the power line, and is connected tothe lower electronic control units via another power line; and theintermediate electronic control unit is in a standby state in which boththe power line and the another power line are open, until receiving aninstruction from the upper electronic control unit.